When I did mine quite a while ago, when I had finished all but one of the exercises, I only needed one point to finish successfully. That means I just had to do it, with the actual score not making any difference. That one test was the 100 yard diver tow. I happened to be waiting to do an OW dive with my instructor on a dive boat in Key Largo, and I suggested that I just do the skill right there and then. There was a pretty fair current and choppy conditions, but since my time didn't matter, I said I would just tow someone away from the boat for more than 50 yards and then tow him back. The instructor agreed, and off I went.
The conditions were far worse than normally occurs on a DM test, but doing it that way was a real revelation to me. As I was towing the diver through the chop and against the current and getting understandably tired as I did it, it dawned on me that I was doing precisely something I might really have to do as a DM, and the life of the person I was towing could be at stake. I realized that those skills were not something I wanted to just scrape by on in order to pass the test. I needed to have the skill and stamina to be able to rescue someone in adverse conditions if that became necessary.
So my message is this. If you have any concerns about your ability to pass this test, then please go to a pool and practice, practice, practice until you are sure that you not only can pass the test, but you can ably assist a struggling diver while serving as a DM later on.